Egypt's military, the biggest recipient of U.S. military aid after Israel, is in decline, according to American diplomats, who blame the Arab nation's top brass for failing to modernize and adapt to deal with new threats.

U.S. diplomatic memos leaked this month show previously unknown friction between the two allies over military assistance and strategy. Military cooperation has always been seen as an unshakable link between Egypt and the U.S., even as the political side of the alliance has gone through public ups and downs over Washington's on-and-off pressure on reform and human rights.

The disagreements, the memos show, are over a wide range of topics, with the U.S. pressing Egypt to focus its military toward terrorism, halting cross-border smuggling and helping out in regional crises. They also suggest that, to the dismay of the Americans, the Egyptian military continues to see Israel, its enemy in four wars spanning 25 years in the last century, as its primary adversary 31 years after the two neighbors signed a peace treaty.

"The United States has sought to interest the Egyptian military into expanding their mission in ways that reflect new regional and transnational security threats, such as piracy, border security, and counterterrorism," said a memo dated Dec. 21, 2008, released by WikiLeaks.

"But the aging leadership, however, has resisted our efforts and remained satisfied with continuing to do what they have done for years: train for force-on-force warfare with a premium on grounds forces and armor."

The memos exposed that public talk of shared goals between the U.S. and Egyptian military is just rhetoric, says Steven Cook, a fellow at the New York-based Council on Foreign Relations and the author of a book on the Egyptian military.

"There doesn't seem to be much more and there hasn't been much for a while," he said. "The U.S. criticism further reinforces what the Egyptian military is all about — the ultimate instrument of political control. They are not there to project power, but to protect the regime."

The military is the power base of the regime of President Hosni Mubarak, himself a former air force pilot. The army ousted the monarchy soon after it seized power in a 1952 coup and all of the country's our presidents since have come from the ranks of the military.

Egypt has its own complaints, too.

Egyptian military officials don't welcome pressure by the Americans to change the doctrine of their armed forces. They also complain that Washington has increased annual military aid to Israel — growing from $2.55 billion in 2009 to an expected $3 billion in 2011.

Since its peace deal with Israel, Egypt has received nearly $36 billion in military assistance — an annual installment of $1.3 billion.

With an estimated 1 million active and reserve personnel, the Egyptian military's last combat mission was in the 1991 Gulf War, when it fought as part of a U.S.-military alliance to liberate Kuwait from Iraqi occupation.

According to the leaked U.S. memos, Egyptian officials told visiting U.S. defense officials they must convince Congress that Egypt was worth more than the $1.3 billion a year it is getting in military aid, according to a memo dated Feb. 28, 2010.

In the memos, U.S. diplomats lament that the Egyptian military has a "backward" posture and has been resistant to U.S. efforts to "adjust its focus to reflect new regional and transnational threats."

They also criticize the military for assuming a direct role in the Egyptian economy, saying it "stifles free market reform" with large military-owned companies active in industries like retail, construction and hospitality.

One memo specifically singles out Egyptian Defense Minister Mohammed Hussein Tantawi, in office since 1991, as the "chief impediment" to U.S. efforts to develop military ties between the two allies.

"During his tenure, the tactical and operational readiness of the Egyptian Armed Forces has decayed," a memo addressed to U.S. Gen. David Petraeus ahead of a visit he made to Egypt in 2008. Petraeus is now the top commander of the NATO force in Afghanistan.

Egypt has resisted sending troops to Iraq and Afghanistan and only recently started training military personnel from the two nations where U.S. forces are fighting stubborn insurgencies.

Instead, the memos say, Egypt places emphasis on trying to achieve military parity with Israel through the acquisition of modern conventional arms such as aircraft and tanks.

One U.S. diplomatic memo said Congressional debate to review — and attach conditions to — aid to Egypt may act as a pressure tool to force the Egyptian military to change its doctrine.

Hossam Sweilam, a retired Egyptian army general, says Egypt continues to view the defense of Sinai, the mostly desert peninsula standing between mainland Egypt and Israel, as its core mission. Despite the peace treaty with Israel, he said, there are recurrent threats from Israeli officials that justify this doctrine.

"The U.S. should not impose on us reformulating our military the way it wants, which we think is ultimately what suits Israel and we don't want to do what suits Israel."